Optics: measuring and testing – Document pattern analysis or verification
Reexamination Certificate
2008-06-02
2010-11-16
Punnoose, Roy (Department: 2886)
Optics: measuring and testing
Document pattern analysis or verification
C382S124000, C382S125000
Reexamination Certificate
active
07834988
ABSTRACT:
In one embodiment, a fingerprint sensing system includes a interference narrow band pass filter, a holographic optical element, a transparent slab stacked together with optical cement. The finger is placed on the filter and illuminated by a narrow band source, the center of its band shifted appropriately with respect to the pass band of the interference filter. A camera on the other side of the slab receives the fingerprint image. The light from the valleys and ridges propagating in the direction of the camera are blocked by the interference filter. The light from the ridges at steep angles are bent by the holographic optical element and then directed towards the lens. This way the ridges are seen by the camera, but not the valleys. In another embodiment, a miniaturized version, the interference filter, a modified holographic optical element, and a blocking filter (if necessary) to block room light can be sequentially attached to the image sensor. In yet another embodiment, the interference filter can be directly coated over an image sensor creating a very simple fingerprint sensor. The principle behind all of the above embodiments is the same, viz: the spectral transmission band of an interference filter shifts with change in the angle of incidence.
REFERENCES:
patent: 3716301 (1973-02-01), Caulfield et al.
patent: 5629764 (1997-05-01), Bahuguna et al.
patent: 5650842 (1997-07-01), Maase et al.
patent: 5892599 (1999-04-01), Bahuguna
patent: 6038043 (2000-03-01), Bahuguna et al.
patent: 6324020 (2001-11-01), Teng et al.
patent: 7574023 (2009-08-01), Sano et al.
LandOfFree
Fingerprint sensor using a spectral filter and a holographic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fingerprint sensor using a spectral filter and a holographic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fingerprint sensor using a spectral filter and a holographic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-4251936